An estimated 1 to 3% of energy from the Sun that hits the earth is converted into wind energy. This is about 50 to 100 times more energy than is converted into biomass by all the plants on earth through photosynthesis. Most of this wind energy can be found at high altitudes where continuous wind speeds of over 160 km/h (100 mph) occur. Eventually, the wind energy is converted through friction into diffuse heat all through the earth's surface and atmosphere.

The origin of wind is simple. The earth is unevenly heated by the sun resulting in the poles receiving less energy from the sun than the equator does. The differential heating powers a global atmospheric convection system reaching from the earth's surface to the stratosphere which acts as a virtual ceiling.

Wind power is the conversion of wind energy into more useful forms, usually electricity using wind turbines. The power in the wind is extracted by allowing it to blow past moving wings that exert torque on a rotor. The amount of power transferred is directly proportional to the density of the air, the area swept out by the rotor, and the cube of the wind speed. Most modern wind power is generated in the form of electricity by converting the rotation of turbine blades into electrical current by means of an electrical generator. In windmills wind energy is used to turn mechanical machinery to do physical work, like crushing grain or pumping water.

Wind energy is abundant, renewable, widely distributed, clean, and mitigates the greenhouse effect if used to replace fossil-fuel-derived electricity.